pull up resistors on parallel port?
26 Oct 2010 18:38 #4881
by jtbarclay
pull up resistors on parallel port? was created by jtbarclay
I'm just messing with motors and my driver boards and getting everything running with emc before I build any hardware,
I'm using easydriver v3 boards. The problem is the 1.7v signal from my parallel port isn't enough to set the direction pin high. Just messing around I put in a 100ohm resistor between the dir pin and v+ (12v for my motors) and both directions worked. Although it got very hot, running 1.44W through a 1/4W resistor usually doesn't end up working. So I tried 100k and then a 10k resistor, neither worked.
I need to go home and search for a 1k resistor still. What is the maximum current I can sink through the low parallel pin? Or is this a bad solution, does anyone have a recommendation?
Thanks,
Jon
I'm using easydriver v3 boards. The problem is the 1.7v signal from my parallel port isn't enough to set the direction pin high. Just messing around I put in a 100ohm resistor between the dir pin and v+ (12v for my motors) and both directions worked. Although it got very hot, running 1.44W through a 1/4W resistor usually doesn't end up working. So I tried 100k and then a 10k resistor, neither worked.
I need to go home and search for a 1k resistor still. What is the maximum current I can sink through the low parallel pin? Or is this a bad solution, does anyone have a recommendation?
Thanks,
Jon
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26 Oct 2010 19:47 - 26 Oct 2010 19:51 #4885
by andypugh
Replied by andypugh on topic Re:pull up resistors on parallel port?
They will normally sink about 15mA, but some will only source 3mA.
1.7V seems broken, is it that low with nothing connected?
I would be more inclined to pull up to 5V (you can source 5V with the same 0V reference from a USB socket)
What is it connected to? It the inputs are opto-isolators then they might work best with +5V to the + of the Opto, and your P-Port connected to the -ve side. That is certainly the way my drives expect to be connected, and they include the right resistor to make that work.
1.7V seems broken, is it that low with nothing connected?
I would be more inclined to pull up to 5V (you can source 5V with the same 0V reference from a USB socket)
What is it connected to? It the inputs are opto-isolators then they might work best with +5V to the + of the Opto, and your P-Port connected to the -ve side. That is certainly the way my drives expect to be connected, and they include the right resistor to make that work.
Last edit: 26 Oct 2010 19:51 by andypugh.
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27 Oct 2010 22:55 - 31 Oct 2010 01:29 #4916
by jtbarclay
Replied by jtbarclay on topic Re:pull up resistors on parallel port?
Opto isolator! Thank you, I don't know why I didn't think of that before. Currently I just have the drivers connected directly to the p-port.
edit: searched my 'tronix stash and found a tube with 39 4n36's inside. Will make new post with my circuit.
edit: searched my 'tronix stash and found a tube with 39 4n36's inside. Will make new post with my circuit.
Last edit: 31 Oct 2010 01:29 by jtbarclay.
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